Amazon formation likened to Stonehenge

Rain forest site possibly used to observe stars.

Rain forest site possibly used to observe stars.

June 28, 2006

SAO PAULO, Brazil (AP) -- A grouping of granite blocks along a grassy Amazon hilltop may be the vestiges of a centuries-old astronomical observatory -- a find archaeologists say indicates early rain forest inhabitants were more sophisticated than previously believed. The 127 blocks, some as high as 9 feet tall, are spaced at regular intervals around the hill, like a crown 100 feet in diameter. On the shortest day of the year -- Dec. 21 -- the shadow of one of the blocks disappears when the sun is directly above it. "It is this block's alignment with the winter solstice that leads us to believe the site was once an astronomical observatory," said Mariana Petry Cabral, an archaeologist at the Amapa State Scientific and Technical Research Institute. Anthropologists have long known that local indigenous populations were acute observers of the stars and sun. But the discovery of a physical structure that appears to incorporate this knowledge suggests pre-Columbian Indians in the Amazon rain forest may have been more sophisticated than previously suspected. "Transforming this kind of knowledge into a monument; the transformation of something ephemeral into something concrete, could indicate the existence of a larger population and of a more complex social organization," Cabral said. While the Incas, Mayans and Aztecs built large cities and huge rock structures, pre-Columbian Amazon societies built smaller settlements of wood and clay that quickly deteriorated in the hot, humid Amazon climate, disappearing centuries ago, archaeologists say. Farmers and fishermen in the region around the Amazon site have long known about it, and the local press has dubbed it the "tropical Stonehenge."